As the number of users viewing information and purchasing items electronically increases, there is a corresponding increase in the amount of advertising revenue spent in electronic environments. In some cases, advertisements are targeted to specific users or to specific web pages or other interfaces to be displayed to users. Advertisements also may be selected based on the content displayed on any number different pages displayed to a user or may also be selected based on search information, such as keywords, entered into a search engine as a user searches for content. Advertisements displayed to a user may also be related to the search results.
Often, an advertisement includes a hypertext link or other user-selectable element that enables the user to navigate to another page or display relating to the advertisement. The page or display relating to the advertisement may provide the user with the ability to purchase the products or services offered by the advertiser either directly from the advertiser or from a provider of the site. Advertisers hope to generate revenue by purchasing sponsored advertisements for display to users most likely to be interested in purchasing or otherwise consuming the products or services being advertised.
Advertising content may be grouped into categories, and advertisers may have a number of electronic advertisements in various categories. New categories of advertisements may be introduced, but determining which categories to introduce presents a number of challenges.